The practice of female sterilization as a method of fertility control began in Puerto rico in the early thirties and increased rapidly during the next three decades. Studies carried out in 1965 and 1968 revealed that approximately one third of all ever married women had been sterilized. For this reason Puerto Rico offers an unique opportunity to analyze the demograhic effect of tis method of fertility control which is the main objective of this project. The other important objective of this research is to determine the impact that the increased utilization of the contraceptive pill has had in the practice of female sterilization in Puerto Rico. An island-wide sample of 2,028 women in the reproductive ages interviewed in 1976 will be utillzed for these purposes. The information obtained included personal characteristics, a pregnancy histoy, a marital history and experience in the use of contraceptive methods. The average number of children of sterilized women will be compared against those not sterilized to determine the effect of sterilization on fertility. A correlation analysis will also be undertaken. In this case fertility will be the dependent variable and some factors associated with sterilization will be considered as the independent variables.